Is it possible to poison someone without having direct contact with him or his food via a third person?

for example: if A want to poison B, is it possible for A to use C as a poison medium without C notice it; given the fact that C is making B's food?

the effect of the poison does not necessary have to result in the death in B, but rather create effects such as disruption of growth, decrease in cognitive ability, disrupt memory, cause erectile dysfunction, weaken immune system, and decrease blood circulation?

if the above assumption is possible in real world

how would B detect it, and further negate the effect of the poison if already consumed

JackBean wrote:you answered by yourself. If A was providing B with food and B used that stuff to cook meal for C...

no, A is not providing B with food, C is.

And my question is if A has not touch the food that B is consuming, is it possible for A to poison B using C. That is if A touches C in any way such as shaking hands, and C is preparing B's food, is it possible to poison B.

mith wrote:Sure, B is allergic to peanuts and C isn't. Also applies for disease resistances such as HIV (C has ccrdelta 5 deletion) or whatever else they're susceptible to.

A gives C some sort of poison/drug/virus but it's not infectious until eaten e.g. polio and C happens to not wash his hands before preparing the food but does wash his hands afterwards.

can you list any poison/ drug that will result in the following effect such as disruption of growth, decrease in cognitive ability, disrupt memory, cause erectile dysfunction, weaken immune system, and decrease blood circulation, but not death?

It goes with the ingestion by B but not by C scenario--dirty hands. As far as I know, the transmission mode of prions includes eating of brain matter from infected animals so I guess if you had a few bits of prions on your hands and it gets mixed with your food, you could end up developing some condition.

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